Knockdown racks having slotted hollow upright posts to which horizontal cross beams are secured by wedge connectors have been widely used for storage shelving and pallet racks. Structures of this type are shown in U.S. Pat. Nos. 2,760,650 to Franks, 2,815,130 to Franks, 3,490,604 to Klein, 3,637,086 to Klein, and 4,421,239 to Vargo.
The wedge connector of the first three and the fifth of these patents is inserted from inside the hollow upright post to secure the horizontal cross beams to the posts, and the wedge connector of the fourth patent is inserted from outside the post. Each of the wedge connectors referred to is formed of a flat, elongated shank with two wedging ears extending laterally from the shank. In the case of the first three and fifth patents, the elongated shank is located within the inside of the hollow upright post when the knockdown rack is assembled, and in the case of the fourth patent the elongated shank is located outside the hollow post when the rack is assembled.
The advantage of positioning the elongated shank portion of the wedge connector within the inside of the upright post, as in the first three and fifth patents referred to, is that the force exerted by the inner edge of the shank against the inside wall of the upright post can be distributed over a relatively large area. However, it is not possible with these wedge connectors to use a completely closed hollow post, since as explained above the connector must be inserted from inside the post.
The advantage to the connector disclosed and claimed in the fourth patent under discussion is that it can be used with a completely enclosed hollow post. However, the portions of the wedge connector that press against the wall of the hollow post abut that wall over a smaller area than with the other four connectors, and it does not have a single, continuous shank portion (supplemented by a second, smaller portion) in contact with the post, as is the case in the other four patents, but instead has three distinct smaller abutment portions making that contact.
The wedge connector of the present invention unexpectedly makes it possible to achieve the advantages of both these types of wedge connectors, without either of the accompanying disadvantages. First, with this wedge connector a large central portion of the elongated shank member, supplemented in the preferred embodiment by a smaller upper portion of the shank, is positioned against the inside wall of the hollow upright post. Second, because of the unique configuration of this wedge connector, it is possible to insert it, quickly and easily, from outside a completely enclosed hollow post.